Timing intermittent fasting with workouts

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TicTacToo
TicTacToo Posts: 76 Member
edited July 2022 in Fitness and Exercise
I'm okay with a 16:8 approach to eating between, say, 12 noon and 8pm then fasting.

However I've recently gone back to doing coached swim training sessions three mornings/week. They're hard work because even the not-very-fit group (me!!!) swims around 2-2.5km in a session. I'm pretty exhausted by the time I drag myself out of the water.

I'm currently 30kg overweight and have some hefty fat stores to fuel myself... they also help me float :-/

How should I time a 16:8 approach to fit with training??? Or should I have an extra meal before or after each session, and not do 16:8 those days?

ETA Specifically, I have swim training early on M/W/F and weights training on T/Th. I did the same program for a couple of years when I was younger and fitter and didn't have any weight to lose... different situation now! I'm
too embarrassed to ask the coach because nearly everyone else at training is ripped and eating extra food to stay that way.

Replies

  • AnnPT77
    AnnPT77 Posts: 32,853 Member
    edited July 2022
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    Ask the coach. Do it privately if you're concerned, and ask for confidentiality. That's why we have coaches.

    That said: If you need more energy for your swim, it would IMO be useful to experiment with whether timing some food around your swim helps your energy level. I'd go with a fair fraction carbs before, and most people would do better if they avoided high-residue foods right before a workout; then maybe some carbs/protein after?

    Truth in advertising, I don't IF. But I have been an athlete at 60+ pounds too heavy, and I did/do take an experiment-based approach to eating/fueling strategies.

    I don't know how vital IF is to you (happiness, compliance, etc.) If it's not essential, I'd consider just setting it aside for a week, and timing some food around the training to see if it makes a difference. Even if you believe that IF has benefits in other ways (autophagy or whatever), would a week away be a major sacrifice? Only you can say.

    It may not even be fueling that's causing your exhaustion. It could be hydration, sleep quality/quantity, overdoing for your current fitness level, etc.
  • sijomial
    sijomial Posts: 19,811 Member
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    I'm a cyclist rather than a swimmer.
    Mostly I skip breakfast (so essentially 16:8 but without defined windows), for regular non-intense rides up to a couple of hours I don't need to have breakfast. Ditto for gym strength training sessions, no fuelling required, no impact to performance fed or fasted.
    But I'm maintaining weight and not in a deficit which may make a difference (especially if you are going for a big deficit).
    I've also been doing this for years and have a generally high carb diet - for intensive exercise where the majority of your energy comes from carbs having a high bodyfat percentage doesn't help much. It would be great for long duration low intensity though.

    But for high performance or long rides skipping breakfast simply isn't optimal for my exercise performance so it's (normally) a big bowl of granola before a ride and extra carbs while I'm riding.

    As time restricted eating is predominantly a tool for long term adherence I don't see any problem in your not doing 16:8 when you have morning workouts/swims. Eating back your exercise calories but before rather than after....

    BTW - as a former sports coach I would only feel positive about someone coming to me asking how to improve their performance whether that's via fitness, technque or diet. They are the kind of people you want to coach.
  • Djproulx
    Djproulx Posts: 3,084 Member
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    You've received some great suggestions from experienced folks in the responses above.

    As someone who has done swim training in the mornings while managing weight with the help of a registered dietician, I followed a 14:10 IF regime, BUT consumed extra carbs either during long or very intense workouts. The RD had me follow my coach's prescribed carb intake during workouts, then resume my IF regimen.

    In your case, that might be as easy as eating a bagel or taking a gel before swimming. And to second the point made by @sijomial, most coaches enjoy discussing nutrition and performance techniques with their athletes.
  • Retroguy2000
    Retroguy2000 Posts: 1,583 Member
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    OP, just checking that you're aware IF is mostly just a tool to help you achieve your calorie intake goals, and that it's CICO deficit that's really powering your weight loss?

    If doing IF is helping you maintain your calorie goals, that's understandable, and I usually do 16:8 or at least 14:10 too, but I don't work out in the morning so it's easier for me. If I were you, I'd just forego IF on those days, while still focusing on total daily goals. It sounds like you'll have a better workout if you do that, which will yield its own benefits too.
  • TicTacToo
    TicTacToo Posts: 76 Member
    edited July 2022
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    Thanks, folks. Yep, I was a bit confused about IF... I've lost weight that way in the past but I can't see it being helpful for any other aspect of getting fitter.

    After reading your posts I summoned some courage and spoke to my coach... she recommends a bowl of porridge an hour or so before training and apple/banana/melon soon after... keeping it simple :-)
  • feisty_bucket
    feisty_bucket Posts: 1,047 Member
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    TicTacToo wrote: »
    .. she recommends a bowl of porridge an hour or so before training and apple/banana/melon soon after... keeping it simple :-)

    Good deal. FWIW, there was a study recently showing no benefit to the 16:8 style of IF.
  • Retroguy2000
    Retroguy2000 Posts: 1,583 Member
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    TicTacToo wrote: »
    Thanks, folks. Yep, I was a bit confused about IF... I've lost weight that way in the past but I can't see it being helpful for any other aspect of getting fitter.
    To clarify, you lost weight in the past by being under maintenance calories. If you took three people and all were on 16:8 IF, one of them under maintenance, one at maintenance, and one above, only one of those people would lose weight.

    I do 16:8 most of the time because I find it benefits my personal schedule. For me that means getting about 60% of my daily calories in the 3-4 hours before my late afternoon workout, instead of those 60% being spread over the previous 7-8 hours.

    Glad to hear you're resolving it with porridge and fruit. I expect you'll feel much better doing that. You'll probably be burning more calories swimming that much than your porridge and fruit will provide anyway, so you'll still be on track for daily calories. Don't forget to keep your protein up too.
  • Djproulx
    Djproulx Posts: 3,084 Member
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    feisty_bucket wrote: »
    TicTacToo wrote: »
    .. she recommends a bowl of porridge an hour or so before training and apple/banana/melon soon after... keeping it simple :-)

    Good deal. FWIW, there was a study recently showing no benefit to the 16:8 style of IF.

    I'd be interested to see a link to this study. I assume you are saying there is no inherent benefit to weight loss from fasting alone if no calorie deficit is achieved during the fasting effort.
  • sijomial
    sijomial Posts: 19,811 Member
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    @Djproulx

    Not sure if this is what @feisty_bucket is referring to but the link below is to Layne Norton's recent review of IF / TRE vs. iso-caloric everyday restriction.

    He makes the great point that if the time restricted eating style of IF makes dieting easier for an individual that's the real benefit - adherence. Ditto the other way round for other individuals of course.
    He has previously covered longer forms of fasting (ADF and 5:2 for example) and again when calories are equated there's no difference for weight loss but does seem to be a greater loss of LBM.

    https://www.youtube.com/watch?v=452HW-PguFU

    Links to studies can be found there.
  • Retroguy2000
    Retroguy2000 Posts: 1,583 Member
    edited July 2022
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    @sijomial Thanks for the video.

    Not just no difference in weight loss, also no difference in many other markers, for IF vs same calories without IF. And as you said, for longer fasting periods like 5:2, IF results in more LBM loss.

    If IF works for you re diet adherence, great.
  • TicTacToo
    TicTacToo Posts: 76 Member
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    Retroguy2000 wrote: »
    You'll probably be burning more calories swimming that much than your porridge and fruit will provide anyway, so you'll still be on track for daily calories. Don't forget to keep your protein up too.

    There are two good things about swimming while overweight:
    1. I burn heaps more calories per hour than I used to when I was smaller ... I think an hour of swim training at my size burns something like 600-700kcal
    2. I've got much stronger legs than before because they're accustomed to carryng the rest of me

    Apart from that I can't say that being 30kg overweight has much going for it!
  • Djproulx
    Djproulx Posts: 3,084 Member
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    @sijomial Thanks for the video. That is in line with other info I've read. I find IF helps me with adherence, making it easier to maintain a calorie deficit.

    Outside of the weight loss discussion, I've been reading some interesting research findings around other benefits observed in IF studies.
  • AnnPT77
    AnnPT77 Posts: 32,853 Member
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    Just as an observation, it seems like for those of us with quite a few decades on the body odometer, IF kind of runs counter to the recommendations of the Prot-Age Study Group**.

    Everyone's gotta find their own individual formula, though - I'm not suggesting otherwise.

    ** https://www.jamda.com/article/S1525-8610(13)00326-5/fulltext
  • Retroguy2000
    Retroguy2000 Posts: 1,583 Member
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    @AnnPT77 Does 16:8 IF run counter to that? I skimmed the beginning of the long article and it was basically saying older folks should increase their protein, though probably there's other stuff later in the article. I could see the 5:2 style of IF running counter to that goal, and it was already mentioned above that 5:2 isn't good for LBM.
  • AnnPT77
    AnnPT77 Posts: 32,853 Member
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    Retroguy2000 wrote: »
    @AnnPT77 Does 16:8 IF run counter to that? I skimmed the beginning of the long article and it was basically saying older folks should increase their protein, though probably there's other stuff later in the article. I could see the 5:2 style of IF running counter to that goal, and it was already mentioned above that 5:2 isn't good for LBM.

    As a generality, it also suggests that it's more important to spread protein through the day as one ages, since we metabolize it less efficiently.

    Seems to me that limiting eating to only a few hours daily is pushing in the opposite direction from that idea. 16:8 isn't the most extreme daily IF protocol, obviously, though. OMAD?

    I'm not saying there's some giant inviolable conflict, just that the time limitations of IF and the recommendation to spread out protein seem to push in opposing directions. We're all going to land where we want/need to land.

    The Prot-Age recommendations, IIRC, talk generically in terms of a hefty chunk of one's protein in each of 3 meals, plus talk about timing some around exercise if quite active. That's from memory, though, and my memory is just as old as the rest of me. 😉
  • Retroguy2000
    Retroguy2000 Posts: 1,583 Member
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    I see, thanks for the info.

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